Existing compact fluorescent lamps are commonly made up of at least one lamp tube, cathode, stem cap and wire. With this type of compact fluorescent lamp, one end of the wire and the cathode are fixed on the stem cap and the other end is led out from the lamp tube. As a result, the whole inner cavity of the fluorescent lamp constitutes the discharge space, such that mercury-vapor pressure is commonly adjusted by partial tube wall at the coldest point; hence, its shortcomings include (1) relatively small adjustment range: it is impossible to achieve desirable effect if condition seriously departs from the norm; (2) difficult to make working state adjustment based on the intersectional effect between amalgam and tube wall at the coldest point for the fluorescent lamp using amalgam. “With the fluorescent lamps increasingly becoming more compact and diverse in characteristics, to a certain extent, it is not easy to obtain satisfactory working state adjustment in wider range with the old cold-end technology such that best effect on fluorescent lamp design is impacted greatly.”